If you want to edit them on your PC, you could always get this:
Blackmagic Design: Intensity
...and then hook up the Sky HD box via HDMI to it (or component video if you get the Intensity Pro and your Sky HD box has the component jacks). That way, you'll be able to record everything off the Sky box in HD, and without losing quality. You'll also be able to record footage off, say, an Xbox 360, as long as it's not copy protected.
The only issue is if Sky ever start using HDCP (High Definition Copy Protection), doing that over HDMI won't work. So you'd need to do it via the component jacks on your box, if it has them.
However, that's the easiest way of getting it onto your PC in HD.
If you don't need HD, then a lot of other devices, both USB and PCI/PCIe based, can capture SD content directly to your PC and you can then edit it that way. The only issue is, with both methods, you'll have to play back the content on the Sky box and record it using your PC, which means that if you want to capture 30 hours of TV, it'll take 30 hours to do it.
